Removal of immiscible fluids from water surfaces and lake beds

ABSTRACT

A method of removing immiscible fluids such as oil spills from the surface of bodies of water which comprises placing an adsorbant compound on the water survace in contact with the immiscible fluid and maintaining contact between the surface of the immiscible fluid and the adsorbant material until the immiscible fluid is adsorbed. The adsorbant compound consists of an admixture comprising from between about 30% and 70% by weight of lead slag mineral wool, with the balance being a finely divided natural stone substance containing substantial quantities of iron, aluminum, and magnesium oxides, including such natural stones as trap rock, basalt and gabbro. The lead slag mineral wool is treated with a hydrophobic-oil-soluble hydrocarbon chain substance, such as oleic acid to wet the surface of the mineral wool prior to mixing with stone flour. The lead slag mineral wool is preferably fragmented into nodules having a diameter of, for example, from 1/2 inch to 1 inch. The composition may be also utilized for removing oil spills from lake beds or soil surfaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of my co-pendingapplication Ser. No. 362,317, filed May 21, 1973, entitled "Removal ofImmiscible Fluids from Water Surfaces and Lake Beds." now abandoned,which application was a continuation-in-part of application Ser. No.296,789, filed Oct. 12, 1972, now abandoned, this application being acontinuation-in-part of a still earlier co-pending application Ser. No.143,713, filed May 26, 1971, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to an improved method ofremoving immiscible fluids such as oil slicks from the surface of bodiesof water or beds, and more specifically to a technique for removing oilssuch as crude or refined oil, gasoline, or the like from these surfacesincluding water surfaces in order to avoid or reduce pollution of thewater. In the past, various techniques and materials have been utilizedfor providing an adsorbant compound for the water, however theseadsorbants have frequently been found to be ineffective in permanentremoval of the pollutant, or have frequently contributed to pollution ontheir own. The concept of the present invention provides a means forremoving pollutants and effectively retaining these materials overextended periods of time, without contributing to the pollution of thewater by incorporation of undesirable materials in the adsorbantcompound. Also, an effective means of mixing the component materials isprovided.

SUMMARY OF THE INVENTION

Briefly, the primary feature or concept of the present inventionprovides for the removal of immiscible fluids by placing an adsorbantcompound on the surface of the water. The adsorbant compound is anadmixture of compacted lead slag mineral wool coated with ahydrophobicoil soluble film such as oleic acid, and between about 30%and 70% by weight of a finely divided natural stone containingsubstantial quantities of the oxides of iron, aluminum and magnesium maybe added, such as, for example, trap rock, basalt or gabbro. Trap rockis generally preferred. Basalt is an Apanitic rock, while gabbro is aPlutonic rock, and all substances are, of course, readily available.

The composition of the adsorbant compound is one which does notcontribute to biological oxygen demand in the water being treated. Thesubstances are highly inert, and are utilized for their highly adsorbantcharacteristics. The rate of adsorption is high, and the retention ofadsorbed oily materials has also been found to be unusually high. Inother words, an oil slick may be removed from the surface of a body ofwater by broadcasting the adsorbant compound upon the surface of thewater, and this oil slick will remain tightly adsorbed by the materialover extended periods of time. Inasmuch as the adsorbant compound isinert, the net affect is a reduction in the extent of pollution of thebody of water. The component materials are preferably mixed together ina closed tumbler.

The adsorbant compound of the present invention has been found to have ahigh affinity for oils such as crude or refined petroleum oils and thelike. The substance will take up or adsorb substantial quantities of oilfrom a water surface, with the quantities adsorbed being extremely highrelative to the weight or volume of the adsorbant compound.

The composition provides a means for cleaning up oil or other chemicalswhich constitute immiscible fluids which have been discharged intobodies of surface water. There appears to be an unusually strong bond orattraction between the oil film and the treated or coated mineral wool.The physical characteristics of the adsorbant treated lead slag mineralwool and rock flour are such that the materials may be placed intocontact with the oil spill, and later skimmed off the surface of thewater prior to complete immersion of the adsorbant material. The coatedor treated mineral wool assists in maintaining the material buoyant overextended periods of time. In certain instances, however, it may bedesirable or expedient to permit the adsorbant material to remain on thewater surface for an extended period of time and permitted to ultimatelysettle to the bottom of the body of water while retaining the adsorbedpollutants.

Therefore, it is a primary object of the present invention to provide animproved method for removing immiscible fluids from the surfaces ofbodies of water which includes placing an adsorbant compound on thewater surface, the adsorbant compound consisting of an admixture ofcompositions which do not in themselves contribute to pollution of thewater body.

It is yet a further object of the present invention to provide animproved method for removing immiscible fluids from the surface ofbodies of water which includes placing an adsorbant compound on thewater surface, wherein the adsorbant compound consists of an admixtureof from between about 30% and 70% by weight of lead slag mineral woolcoated with an oil-soluble hydrophobic film.

It is yet a further object of the present invention to provide animproved material for adsorbing immiscible fluids from the surfaces ofbodies of water which includes an admixture of hydrophobic film coatedlead slag mineral wool pellets and a finely divided inert rock or stonecontaining substantial quantities of the oxides of iron, aluminum, andmagnesium.

Other and further objects of the present invention will become apparentto those skilled in the art upon a study of the following specificationand appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As has been indicated, the adsorbant compound utilized in the presentinvention includes an admixture of from about 30% to about 70% by weightof lead slag mineral wool, balance rock flour. It has been found mostdesirable to employ from between about 45%-55% lead slag mineral wool,balance rock flour. Certain applications of the adsorbant compound maydictate variations in the quantity, however for most oil spills onbodies of water, the admixture of 50% lead slag mineral wool, balancerock flour has been found to be optimum. In order to enhance thecapability of the substance to adsorb and retain water immisciblefluids, a quantity of finely divided trap rock material or powder orother natural stone rich in the oxides of iron, aluminum and magnesiumis added. Best results have been obtained through the addition of amaterial selected from the group consisting of basalt and gabbro. Thismaterial is preferably added in finely divided form, such as in the formof finely divided particles of 50 mesh or smaller.

The lead slag mineral wool is commercially available. This material is aby-product of lead smelting, and normally contains high metal oxidecontent. There appears to be a reasonable attraction between oils andlead slag mineral wool, this affinity being believed to contribute tothe retention of the oil by the mineral wool. The application of thefilm of oil soluble-hydrophobic material to the lead slag wool enhancesthe affinity of the material for oil. Also, prior to mixing with rockflour, the lead slag mineral wool is preferably passed through a hammermill or silage cutter in order to compress the material into fragmentsor nodules approximately 1/2 inch to 1 inch in diameter.

The mineral wool is treated with a material so as to render the surfacecoated with a film of oil soluble hydrophobic material. Preferably,oleic acid is used to form this film, it being understood, however, thatother fatty acids may be utilized, preferably those having from between16 and 22 carbon atoms. Since the most abundant acids have 16 or 18carbon atoms in the chain, and these are commercially available, theybecome more useful for the present concept. In this connection, theacids of the group consisting of palmitic, stearic, oleic, linoleic,linolenic, and arachidonic acids may be found useful. Linoleic,linolenic and arachidonic acids are frequently referred to as "essentialfatty acids." The acids are normally derived from the glycerides.

In order to prepare the substance for use, one part of the acid is addedto approximately 50 parts of water, and the lead slag mineral wool ispassed through the liquid until the fibers become damp. The damp fibersare then mixed with the finely divided trap rock flour. This material,following drying, provides an adsorbant material that floats on watersurfaces for periods of up to 30 days. During this period, the mixedmaterial has a great affinity for oil and certain other water immisciblematerials, and little, if any, affinity for water. The fiber materialsappear to act as a matrix which binds and holds the oil into thecompressed balls or rolls of wool, and the material can be easilyremoved from the water surface. The material has been found to becapable of withstanding constant agitation and will normally hold, andretain up to 12 times its weight of oil. The congealed oil matrixmaterial may float for periods of up to 30 days. Wave action may provideagitation of the material in oily waters, which tends to be helpful inexpediting adsorption.

It has been found that the fatty acids selected from the groupconsisting of palmitic, stearic, oleic, linoleic, linolenic, andarachidonic acids are equally suited to the concept. They are employedby dispersing the acid in water, preferably distilled water, on a basisof approximately 2% acid, balance water. The lead slag mineral wool isexposed to the acid-water mixture to an extent sufficient to permit thewool to become damp, and therefore substantially coated with the fattyacid upon evaporation of the water.

When materials rich in oxides of iron, aluminum, and magnesium areadded, this material may be introduced into the mineral wool while in ahammer mill, or may be physically added prior to use. The technique andnature of the materials permit the finely divided stone material to beconveniently added to the mineral wool.

In actual use, the adsorbant compound is placed upon the surface of thewater in contact with the immiscible fluids such as spilled oil or thelike. The oil is quickly adsorbed into the surface of the lead slagmineral wool-rock flour mixture.

EXAMPLE 1

500 pounds of lead slag wool was passed through a hammer mill andcompressed balls or rolls of the wool were formed. This material wasthereafter wetted with a solution of 2% oleic acid in water andpermitted to dry.

Thereafter, 500 pounds of basalt, 50 mesh and smaller were added to thelead slag wool and the combination placed within a closed tumblerchamber and tumbled for a period of 10 minutes at a rate ofapproximately 50 cycles per minute. A butter churn tumbler may besatisfactorily utilized for this purpose. Following tumbling, thematerial was permitted to settle for 5 minutes within the closed chamberso as to permit the dust to settle and find its way into the intricaciesof the lead slag wool.

This material will pick up at least about 10 times its own weight in oilwhen placed on a water surface containing a superimposed layer of oil,such as petroleum products and the like.

In certain instances, a greater quantity of crushed basalt may bedesirable, particularly when the material is to be used to remove thickheavy films of oil from water surfaces. The upper limit of approximately70% of basalt is felt reasonable in view of the density increase of thematerial when this quantity is employed, since as the density increases,the material has a more rapid rate of sinking within the area beingtreated.

For treatment of surface water wherein the bed is impregnated withtrapped oil or the like, it has been found that the technique is moreeffective when applied during periods of rising barometric pressure. Thereason for this is unknown, however it has been observed that greaterquantities of trapped oil are released from the bed during periods ofbarometric pressure increase.

TREATMENT EXAMPLE

A mixture of 500 pounds of lead slag wool was passed through a shredderto form compressed lightweight balls, these lightweight balls having anominal diameter of approximately 1 inch when formed. This material wasthereafter wetted with a solution of 2% oleic acid in water, andpermitted to dry.

Thereafter, 500 pounds of basalt ground to 50 mesh or smaller was addedto the lead slag wool and the combination placed within a 50 gallon drumand tumbled at a rate of 50 revolutions per minute for a period of 10minutes. Following tumbling, the batch of material was permitted tosettle for 5 minutes to permit dusting to cease, and the material wasthen removed.

This composition is then spread along a shoreline and surface of a lakehaving no surface outlet at a rate of 100 pounds of the lead slagwool-rock flour per acre.

The material ultimately sinks to the lake bottom, and retains theadsorbed and adsorbed oil film therewithin.

GENERAL DISCUSSION

In another operational concept, the lead slag mineral wool and rockflour mixture may be retained or physically confined within ascreen-like enclosure. A coarse mesh screen or the like may be utilizedfor retention of the adsorbant compound. The structure may then beplaced into physical contact with the surface of the body of water, thuspermitting the adsorbant material or compound to be more convenientlyretrieved.

The operating parameters for this concept are the same as those setforth in the operational example hereinabove. The substance is capableof retaining up to twelve times its weight of oil, and with thisparameter in mind, the adsorbant compound is utilized on a weight basiscalculated to retain the appropriate quantities of materials.

In a modified form of the concept, the lead slag wool may initially bespread upon the surface of the oil covered water, and thereafter thetrap rock screenings may be applied to the lead slag wool, previouslydispersed on the water surface.

In certain other applications, particularly where a water level may varysubstantially between highs and lows, the mixed fiber material may bedispersed on the shore line where it has been found to adsorb oil whichmay be retained as a slick on the surface.

In still other applications, trap rock screenings and limestonescreenings may be spread sequentially over the lake bottom following oilremoval, and this activity has been found to be beneficial on thequality of the water following oil removal.

In still a further embodiment, it may be desirable or expedient topermit the adsorbant material to settle to the bottom of the body ofwater and remain there for an extended period of time, particularlyafter it has become loaded with oil, and with the oil being retainedtherein. In this concept, the material is initially spread on the oilslick and permitted to remain therefor a period of several days, afterwhich an additional quantity of trap rock screenings is spread over thefloating mass, in an amount sufficient to sink the mass.

While the precise mechanism is not known, it appears that the placing ofmetal oxides such as iron, aluminum, or magnesium in a body of waterassists in the adsorption of phosphates, nitrates, nitrites, and thelike. The compositions appear to function best when large exposed areasor surface areas are available. It appears that the material creates anenvironment which encourages and speeds bacterial decomposition of theoil and certain other water pollutants.

Typical analyses of materials which have been found particularly usefulin connection with the present invention are set forth hereinbelow:

                    Lead Slag  Basalt                                             ______________________________________                                        Si 02             38.0 %       45.90 %                                        Fe2 03            20.0         14.08                                          Al2 03            7.0          17.35                                          Co 0              26.0         8.93                                           Mg 0              5.0          8.40                                           Total Alkalis as Na2 0                                                                          2.0          --                                             So 3              2.0          3.88                                           ______________________________________                                    

As a further feature of the present invention, it has been found thatthere are a number of lakes, lagoons, oil ponds, rivers, creeks, boatharbors and the like which have their beds and shore lines saturatedwith oil and other water immiscible pollutants. For clarifying theseareas, it has been found that trap rock screenings may be spread uponthe water surfaces, whereupon the larger particles immediately sink,while the finer particles form a temporary white cloud in the water. Thescreenings preferably have a size ranging from approximately 10 mesh toless than 100 mesh, it being understood that the size range is notcritical, but is important from the standpoint of providing asignificant surface area for performing the function, with this type ofmaterial being readily available at that residue taken from the dustcollector of a trap rock crushing operation. This material is knowngenerally as "trap rock flour." The deposit of trap rock screenings of asize of approximately 10 mesh to about 100 mesh has been found todisrupt the oil particles from the lake bed, and permits them to rise tothe surface and form a film in a relatively small or confined area. Thisdischarged or released oil film can then be gathered up with the mixedfiber material on the water surface, or it can be permitted to move ontothe shore line where it may be adsorbed by the mixed fiber material andtrap rock screenings which may have been previously spread on the shoreline.

Copper slag mineral wool may be utilized as a substitute for lead slagmineral wool, with this material not having the requirement of beingpassed through a shredder. It will be appreciated that lead slag wool ispreferred as a material, however.

It will be appreciated that various techniques will become apparent tothose skilled in the art for accomplishing the aspects of the presentinvention. Variations in admixture, method of preparing admixtures, andthe like may be readily employed.

I claim:
 1. The method of removing oil spills from the surface of bodiesof water comprising:a. placing an adsorbant compound on the watersurface and in direct contact with said immiscible fluid and maintainingcontact between said immiscible fluid and said adsorbant compound untilsaid immiscible fluid is adsorbed by said adsorbant compound; and b.thereafter removing said adsorbant compound and adsorbed material fromsaid water surface; c. said adsorbant compound conssiting of anadmixture of from between about 30% and 70% by weight of particulatelead slag mineral wool, balance of from between about 70% and 30% rockflour, said lead slag mineral wool having a film of an oil solublehydrophobic film thereon, said rock flour being selected from the groupconsisting of trap rock, basalt and gabbro, and having a particle sizeof up to about 50 mesh.
 2. The method as set forth in claim 1 beingparticularly characterized in that said adsorbant compound consists ofan admixture comprising between about 45% and 55% lead slag mineralwool, balance of from between about 55% and 45% rock flour.
 3. Themethod as set forth in claim 1 being particularly characterized in thatsaid adsorbant compound consists of an admixture comprising 50% leadslag mineral wool, balance of 50% rock flour.
 4. The method as definedin claim 1 being particularly characterized in that said oilsolublehydrophobic film is a film of a fatty acid selected from thegroup consisting of palmitic, stearic, oleic, linoleic, linolenic, andarachidonic acids.
 5. The method of removing oil spills from the surfaceand bed of bodies of water comprising:a initially spreading a certainfinely divided particulate solid upon the surface of the water, andpermitting the composition to settle to the bed surface, said certainparticulate solid being selected from the group consisting of trap rock,basalt and gabbro, and having a particle size of up to 50 mesh; bthereafter placing an adsorbant compound on the water surface in contactwith said immiscible fluid and maintaining contact between saidimmiscible fluid and said adsorbant compound until said immiscible fluidis adsorbed; and c removing said adsorbant compound and adsorbedmaterial from said water surface; d said adsorbant compound consistingof an admixture comprising from between about 30% and 70% by weight ofparticulate lead slag mineral wool coated with a film of anoil-soluble-hydrophobic film, balance of from between 70% and 30% rockflour, said rock flour being selected from the group consisting of traprock, basalt and gabbro, and having a particle size of up to about 50mesh.